Decentralised Mechanical Extract Ventilation (dMEV)

Also known as System 3 in Approved Document F of the Building Regulations, decentralised Mechanical Extract Ventilation (dMEV) systems incorporate continuously running extract fans, designed to remove waste and moist air from a single wet room. dMEV fans continuously extract the waste air at both low trickle or boost speeds, as determined by the homeowner through a range of control options. Replacement fresh air is then drawn into the dwelling via background ventilators located in the habitable rooms.